This invention relates generally to a heating apparatus and method and in particular to an airtight heating apparatus and method adaptable for efficiently burning both coal and wood.
As the price of oil and gas fuels increases, more and more households are turning to wood burning and coal burning apparatus to provide at least a portion and in some circumstances all of the heat for a dwelling. In some instances fireplaces are used. However the fireplace is an inefficient heater; and in response to the increased demand for wood burning and coal burning heating apparatus, a myriad of free standing stoves have been commercially designed and manufactured.
One class of particularly efficient stoves are those stoves which have controlled air inlets. These stoves, often termed airtight, can have many different configurations. Two of the airtight wood burning stoves, which are particularly successful, are capable of operating using horizontal or updraft combustion. They are the Vigilant.TM. and the Defiant.TM., both manufactured by Vermont Castings, Inc., Randolph, Vt., the assignee of this application. The Vigilant and the Defiant are both relatively large heating apparatus having heat outputs, at maximum burning capacity, of about 45,000 and 55,000 BTU's respectively. In addition to the wood burning stoves which have recently become quite popular in today's era of high oil and gas prices, many homeowners, who have grown weary of the multistep procedure of buying wood, perhaps splitting and stacking it, and then bringing it into the house, have turned to coal burning stoves as an alternative method and apparatus for heating the house. These stoves, long in use on the European continent, are designed solely for burning coal, many of them being well controlled and efficient.
A stove design able to efficiently burn either coal or wood, without a major structural change has not yet been created. The primary reason for this apparent gulf in the stove art is the vastly different operating parameters which relate to the many differences between the two different fuels, and the resulting inability to marry, in one apparatus, a structure efficient for both fuels.
An object of this invention is therefore an airtight heating apparatus and method having the capability of efficiently burning either wood or coal without major structural changes, and which is long lasting, reliable, practical and efficient. Other objects of the invention are a heating apparatus and method wherein the user can service the apparatus and convert it easily from a coal burner to a wood burner (and vice versa), and which can be reliably manufactured with minimum cost.